Flow indicator



E. W. DAVIS FLOW INDICATOR Oct. 3, 1944.

Filed oci. 19 ,y 1942 III ///v/// Y l l Patented Oct. 3, 1944 UNITED STATES PATENT OFFICE y j A Y 2,359,467 I FLOW INDICATOR I Ernest W. Davis, River Forest, Ill. Application October 19, 1942, Serial No. 462,657

12 Claims.

My invention relates to flowindicators for indicating the flow of viscous fluids or semi-lluidsy and is especially adapted forrindicating the ow ofgrease or heavy oil discharged by lubricating systems into machine bearings.

One object' of my invention is to provide a device of the class described which is capable of indicating a very small rate of flow.

Another object is to provide a flow indicator wherein the flow of lubricantV therethrough is clearly visible at a distance.

Another object is to 'provide a device of the class described in which, the flow is substantially magnied.

Another object is to provide a device of the class described which will withstand a pressure of severalV thousand pounds per square inch.

A further object is to provide a device of the class described which comprises but few parts, and which can be manufactured at low cost. These an'd other objects will appear as the description proceeds.

' In the drawing:

Figure 1 is a central, longitudinal `section of one embodiment of my invention which is especially adapted-for withstanding high pressure;

AFigure -2 is a central, longitudinal section of another embodiment, which is particularly adapted for attachment to a source of lubricant pressure.

Figure 3 is a central, longitudinal section of a third embodiment which is particularly adapted for being attached directly to a bearing requiring lubrication; and

Figure 4 is a transverse section of the flow indicator shown in Figure l, and illustrates the refraction of light waves whereby the indicated rate of `flow is substantially magnified.

Flow indicators of the type herein shown are useful for indicating the flow of lubricant in centralizedl lubricating systems, wherein lubricant delivered at high pressure from a single source" is distributed by means of tubes to a plurality ofbearings requiring lubrication. In someg'installations it is desirable to attach the flow indicators directly to the bearings to be lubricated; under conditions Where the bearings are not accessible for observation the flow indicators may be located at the source of lubricant pressure; and in other installations it may be most advantageous to install the indicators at intermediate locations inthe lubricant line. The embodiments herein shown, and described hereinafter, are adapted for Yall vthese conditions.

Referring to the construction illustrated in Figure 1, the cylindrical, tubmar member 5 is constructed of methyl methacrylate plastic,V

which is particularly suitable for this part owing to its high tensilestrength, its low absorpare bent in a manner that produces substantial magnification.

The helical rotor 6 lits closely in the tubular member 5, but not tight enough to bind and prevent rotation. twisting a steel bar about its longitudinal axis;

then turning down the ends to provide the pivots 1, 1; and then grinding in a centerless grinder to provide'arcuate shaped edges (as shown in Figure 4) which conform with the bore of the tubular member 5.

The tubular member 5, Figure 1, is provided with screw threads I I, I I for attaching the metal end pieces 8, 8, which are provided with pipe threads 9, 9 for attachment in the lubricant line.

Each end of the tubular member 5 is provided withv a tapered portion I0, I0, which lits in the end piece 8 to provide a leak proof seal, the tapered portion I0 being forced outwardly by the high pressure of the lubricant. The diameter at the eXtreme end of the tapered portion Y IIJ is about one quarter the diameter of the threads II, so that the transverse area is only one-sixteenth as large, whereby the unit stress on the vthreads Il, Caused by the lubricant pressure, is not excessive.

This construction, combined with the relatively small bore of the tubular member 5, permits the use of a relatively weak, non-metallic, transparent substance for the tubular member 5, wherebyl visible action under high pressure may b'e secured without the necessity of using external, metal tension members extending from end to end, such as are commonly used where a transparent tube is subjected to high pressure. In the construction shown, the longitudinal tension of the tubular member 5, provides the sole reactiveV force for resisting the longitudinal force tending to separate the end pieces 8, 8, due to the lubricant pressure, and therefore no external tension members are required.

Each end piece 8 is provided with eccentric openings I2, I2, foi` permitting lubricant to ow through the indicator. The unperforated portion I3, at the center, actsras a thrust bearing for the pivot l. It will be observed that the bore of the tubular member 5 forms the only radial bearing for the rotor 6, so that the rotor The rotor 6 is constructed byv the indicator of this invention, thek plain thrust bearings, without radial action, are adaptable for inexpensive manufacture by high production methods, and provide a floating rotor which is free to acquire the most advantageous positionkv for its uninterrupted rotation.

The operation of this indicator is quite obvious. the tubular member 5, tends to ilow without rotation, due to its inherent viscosity, and its contactwith the bore of the tubularlmember- 5.1 The; reaction produced by this resisting forcev of" vis.

cosity, causesrotationf of :the rotor 6, which: Ito;- tationi permits the-lubricant` to follow its tend'-` ency to.l move longitudinally withoutl rotation;

This operatingl principle-.is quite diITerent fromA that of similar devicesy used with non-viscous liquids, whereinv the force of momentum causes. rotation of a helical rotor. The force of; mo'- mentum varies with the square of the velocity,

and when vthe velocity is; very low, no; rotation; ofY

the rotor; will; occur. Butin the deviceiof this invention, wherein viscous lubricantV is usedthezrotor responds to any rate; offflow, no matterhoW low.

Referring to Figure 4; the 'lm of lubricant-V between the arcuate shapedgedgeof the rotor, lv` and the tubular member '5, is relativelythinv so that motion of theed'ge of, therotor 6 isvisible even when; the indicator is, used with darkf cole' ored'lubricants. In. order toysecure thisvisibility,v

- light: must-l trfavel throughY the lubricantA 111m'V twice; it must first travel through the film of," lubricant to'illuminate thewrotor, and theligh't' reflected by the rotor mustv then travel bachi` through-the lubricantV film to reach the observers eyes. Therefore, .the clearance between ther-.otor

6, andthetubul'anmember 5, mustbe less Athan, halt the penetrating distance-of light through the most opaque lubricantV thatis to ber used.

The'ymotion of the rotor 6Y is-made more appar= ent by; the magnifying` action oft the tubularl` member 5, as illustrated in Figure 4r, Light waves` rellected by the rotor 6 along. the. lines- I4, I4 are retracted asthey'leave thetubular member,

and'gthen follow/the lines. I5, I5 tothe observers. eyes.V This produces an apparent diameter of therotor 6; equal tothe distance between'. the.l The degree: of refractioniis'V determinedby the relative.Velocitiesywith whichv light wavesY are propagated through thel material of the tubularfmember'5; and through air; or`

inrother words, by the index ofV refraction o1?` methyl methajcylate plastic, whichfishighly Satisfactoryfor-'this purpose.

The embodiment illustrated in Figure 2 is vpar- Y ticularly adaptable for use inY a multiple pump,

wherein a common driving mechanism actuates'A a plurality oi"l lubricantpumps, all receiving lu'- bricantfrom a: commonv source, and each discharging; lubricant inv measured amounts to ak eorrespondingtube leading to one ofthebearings onthe machiner which is to be lubricated. A flow indicator is `attachedto thev outlety of 'each- Lubricant passing through the bore .of'z

pump, and these iiow indicators aiord visible indication of the amount of lubricant supplied to each bearing.

In such an installation, each transparent tube I8 screws directly into one of the pump outlets I9, and is threaded at the lower end for attachment to the tube coupling 20, which is provided with a bushing 2| for securing the copper tube 22 leading to a bearing requiring lubrication. The rotor 23 is similar to the rotor 6 in Figure 1, but has only.: one pivot 24 (Figure 2)', which rests on the thrust; bearing 2 5, integral withv the coupling 20. f

When all the bearings on a machine are accessible for convenient observation, it may be desirable to attach each flow indicator directly to. a bearing, as illustrated in Figure 3. VHere, the lower end of the transparent tube 26 is provided with aV pipe thread 2l for attachment to thebearing 28. The thrust bearing 29 is threaded into the tube 26. The rotor 30 and pivot 3l are similar to those previously described'. 'Ihe upper end oi` the tube. 2B is threaded toreceive the coupling bushingf32, and is prov-ided'withaI taperedgportion 33 for making a lubricant-tight seal with the flared copper tube 34, through;

whichlubricant is supplied tothe bearing28.

I claim:V

1. In a flow indicator for a centralized lubri... catingf system, a transparent: tubular member having a. relatively small bore therein and 'having a tapered sealing portion at' the upper-endSthere-f off,` said tubular member havingscrew-threads at". each endV thereof, and' the screwV threads atf the lower end being adapted for screwing'directly.l

into aA bearing to beflubricated; a .bushing having threadsfor engagementY with the threadsy at the;

upper.l end offsaidftubular member, said: bushing being; adapted to compress a dared metaltube against said tapered sealing portion whereby said metal tube and said transparent tube-may be coupled together to forma; lubricant tightjoint;

a helical-shaped rotatable member withinsaid' tubular member, and visible therethrough; and

a. thrust bearing for limiting the-downwardmove- Y ment of said rotatable member.

2.: In. allow indicator for a highfpressureY 11ubricating system, a transparent tubular.v member;

a helical-shaped rotatable member rot'atlvel'y supported'within said tubular member and visible therethrough; and a metal end piece secured-to whereby; lubricant pressure within said tubular. y member will force said edge against said endv piece to forma lubricant, tight seal therewith.

3. In a ow. indicator forV a highu pressure 1ubricating System, a transparent. tubularv memberv having, a threaded end; a helical-shapedrotat.-

able member withinV said tubular member. and..

visible therethrough;` athrust bearing for. limit:

ingkv longitudinal movement, ofsaid rotatable member; .and a metal end piece screw threadedto said threaded endot saidn tubular member, said end piece having asealing portion` engaging. with..

a corresponding sealing portionon said tubular member forforming. a lubricant tight seal` therewith,and .the transverse area. of said. threaded, end being several times as -largeas .the transverse area of the sealing" portion of said tubular member, whereby said flow indicatorma-y-besubf-A jected to high lubricant pressurewithout strip.

ping the threads at said threaded end of said tubular member.

4. In a flow indicator, a transparent tubular member; a rotatable helical member within said tubular member and visible therethrough; two metal end pieces, one screwed onto each end of said tubular member, each end piece having a thrust bearing integral therewith, and said thrust bearings confining only longitudinal movement of said helical member.

5. In a flow indicator, a transparent tubular member having an inlet end and an outlet end, said tubular member being threaded at its outlet end for screwing directly into a bearing; means at the inlet end of said tubular member for connecting said tubular member with a lubricant line; a rotatable helical member within said transparent tubular member and visible therethrough; and a thrust bearing secured directly to said tubular member and confining longitudinal movement of said helical member.

6. In a iiow indicator, a transparent tubular member; a helical member rotatively supported in said tubular member; and a single thrust bearing for said helical member, said thrust bearing being positioned to oppose longitudinal movement of said helical member under the influence of the resultant of the forces of gravity and lubricant pressure.

7. In a iiow indicator, a transparent tubular member; a tube coupling including a body member and a tube-compressing member; a helical member rotatively supported in said tubular member; means for securing said body member to said tubular member; and a thrust bearing for said helical member, said thrust bearing being integral with said body member and being positioned to oppose longitudinal movement of said helical member under the influence of the resultant of the forces due to gravity and lubricant pressure.

8. In a flow indicator, a transparent tubular member having an inlet end and an outlet end, said tubular member being threaded at its inlet 'end for direct connection with a high pressure lubricant discharge mechanism; a tube coupling including a body member and a tube-compressing member; means for securing said body member to said tubular member; a helical member rotatively supported within said tubular member; and a single thrust bearing for said helical member, said thrust bearing being carried by said body member and being positioned to oppose longitudinal movement of said helical member under the influence of the resultant of the forces due to gravity and lubricant pressure.

9. In a device for indicating a flow of lubricant in a high pressure lubricating system, `a bearing for supporting a rotating shaft; a screw-threaded, lubricant-inlet opening in said bearing; a transparent tubular member having an inlet end and an outlet end, said outlet end being threaded to t said screw-threaded opening, whereby said tubular member may be attached directly to said beaning; and a helical member rotatively supported within said tubular member.

10. In a flow indicator, a transparent tubular member having an inlet end and an outlet end; means for connecting said inlet end with a lubricant line; a helical member rotatively supported within said tubular member and visible therethrough; and a single thrust bearing for said helical member, said thrust bearing being secured to said tubular member.

1l. In a flow indicator, a transparent member having a lubricant-conducting bore extending therethrough; a rotatable helical member within said bore; and a thrust bearing for said rotatable member, said thrust bearing opposing longitudinal movement only of said rotatable member in the direction of the resultant of the forces of gravity and lubricant pressure, and the surface of said bore forming the sole radial bearing for said rotatable member.

12. In a device for visibly indicating the flow of relatively opaque lubricant in lubricating apparatus, a transparent tubular member having a cylindrical bore therein; a rotatable helical member within said bore; and a bearing opposing only longitudinal movement of said rotatable member under the influence of the resultant of the forces due to gravity and lubricant pressure, the clearance between said helical member and said bore being less than half the penetrating distance of light through the most opaque lubricant used in said lubricating apparatus, whereby rotation of said helical member caused by the flow of said lubricant through sa/id bore may be observed through said transparent tubular member, and whereby the approximate relative quantity of lubricant passing through saidv now-indicating device is visibly indicated.

ERNEST W. DAVIS. 

